The problem with pixel-only data
Browser pixels miss conversions because of ad blockers, browser privacy features and cross-device journeys. When you scale on that data, you may cut winners and keep losers.
What server-to-server postbacks fix
An S2S postback sends the conversion directly from the affiliate network or your server to the tracker, tied to the original click ID. It does not depend on the visitor's browser.
A pre-scaling checklist
Confirm click IDs pass through every redirect, test a postback end to end, compare tracker numbers with network numbers, and pass conversions back to the traffic source so its algorithm learns from real data.